This invention relates to compound shift levers formed of coupled elongated sections. More particularly, the invention relates to an improved vibration dampening coupling for the sections.
Most of the prior art compound shift levers comprise two sections for the purpose of providing a vibration dampening coupling for isolating transmission gear noise and lever chatter caused by torsionals from the engine through the transmission. Most of such vibration dampening couplings utilize elastomer, which has been found to be quite successful in the isolation of vibration. In the typical two-piece shift lever, a generally hollow section partially overlies a first solid cylindrical section. The couplings, interposed between the two sections, are generally elastomer bushings or "donuts" which must be of a design and composition sufficient to handle and withstand a very high frequency cycle of radial loads over the useful life of the shift lever. Typically, however, the elastomer coupling becomes crazed and brittle over its useful life, and loses its dampening effectiveness. This happens primarily because the shift efforts are fully supported only by the bushings, and there is no backup for rigid and more substantial support available for carrying the radial loads imposed between the two shift lever sections.